1. Field of the Invention
The present invention relates to an apparatus for measuring an object's distance, wherein the apparatus is used in a camera having a multi-point object distance measuring device (a multi-point measuring device) and a picture plane size varying device.
2. Description of Related Art
A camera is known to have a picture plane size varying device which can change the size of an image area, for example, between a large (standard) size image area and either a half-size image area or a panoramic image area. In such a known camera having an image area size varying device, an object's distance is measured by an object distance measuring device which measures the object's distance from the camera, corresponding to the image at the center of the image area or the vicinity thereof. Namely, the object distance to be measured is the distance between an object to be taken, corresponding to an image at the center of the image area (including the vicinity thereof) and the camera, resulting in little or no possibility of error in measurement.
Recently, cameras having a multi-point measuring device, which measures the object distance corresponding to a plurality of images at various measuring points (measuring zones) of the image area, have been on the market. Such a multi-point measuring device is usually realized by a divided measuring device (evaluation measuring device) in which the measurements at a plurality of measuring points are evaluated to determine an optimum exposure condition.
Generally speaking, a pattern of the measuring zones is determined, based on those in the standard image area (large image area). Therefore, if the image area is changed (i.e., if the size of the image area is changed), the measuring zones will not correspond to the image area and a measurement error will likely result.